Synthesis of amphiphilic polycyclooctene-graft-poly(ethylene glycol) copolymers by ring-opening metathesis polymerization

In this paper, a novel monomer of 4-methyl-3-(carbamate)-carbanilic acid-4-cyclooctene ester (MCCCE) was synthesized and characterized by FTIR, NMR and ESI-MS. Polycyclooctene-graft-blocked isocyanate copolymers were prepared by the copolymerization of MCCCE and cyclooctene via ring-opening metathesis polymerization (ROMP). Amphiphilic polycyclooctene-graft-PEG copolymers were prepared by melt mixing the polycyclooctene-graft-blocked isocyanate copolymers with poly(ethylene glycol) (PEG) at 200 °C. The blocked isocyanate group on MCCCE can be dissociated to produce free isocyanate group, which will react with the end hydroxyl groups on PEG molecules. The effects of monomer-to-catalyst, monomer-to-chain transfer agent ratios on molecular weight of the copolymer were detailedly studied. The water contact angle of polycyclooctene-graft-PEG copolymer is much smaller than that of polycyclooctene.